1. Field of the Invention
The present invention relates to an image processing apparatus having a continuous capture function and an image management apparatus and an image management method and a computer program that manage a plurality of continuously captured images. In particular, the present invention relates to an image processing apparatus, an image management apparatus and an image management method, and a computer program that select a representative image desired by a user from a plurality of continuously captured images.
More specifically, the present invention relates to an image processing apparatus, an image management apparatus and an image management method, and a computer program that automatically select a representative image from a plurality of continuously captured images. In particular, the present invention relates to an image processing apparatus, an image management apparatus and an image management method, and a computer program that automatically select a representative image from a plurality of continuously captured images of a subject such as a person in accordance with whether the subject is captured well or poorly in the images.
2. Description of the Related Art
Recently, so-called digital cameras are widely used in place of film cameras. The digital cameras capture images with a solid-state imaging element, with its light receiving sections for photoelectric conversion and charge accumulation arranged in a matrix and formed by photodiodes, in contrast to the film cameras in which images are captured using films and photographic plates. Examples of the solid-state imaging element include CCD (Charge Coupled Device) and CMOS (Complementary Metal Oxide Semiconductor) sensors. The CMOS sensors have advantages that they consume less power than the CCD sensors and that they are driven on a single low voltage and are easy to integrate with surrounding circuits.
Camerawork for the film cameras and camerawork for the digital cameras are basically the same as each other. Along with digitalization of captured images, technologies for automating or assisting camerawork such as automatic exposure control, automatic focus control, and hand-shake correction have been developed, reducing the possibility to fail in capturing to be extremely low even for users unskilled in operating cameras.
Continuous capture may be mentioned as one way for users to capture desired images. In the continuous capture, an identical subject is captured continuously a plurality of times. The continuous capture is especially effective in the case where the subject is a moving object such as a person, for example, because it is difficult for the user to timely press a shutter button. However, the continuous capture incurs a problem that it is necessary to select which images to keep and which images to discard from a plurality of continuously captured images. Well captured images and poorly captured images are mixed in the continuously captured images, and if the images are not selected appropriately as to which to keep and which to discard, the well captured images may be lost, making searches troublesome. In addition, the poorly captured images are basically not necessary and may consume storage space wastefully if the poorly captured images are left undeleted. Hereinafter, an image selected as a well captured image from a plurality of images is referred to as a “representative image”.
An image management method in which a plurality of images are extracted in the chronological order from successive images such as a movie file and an index screen in which reduced versions of the plurality of extracted images are arranged in one screen is prepared to store the index screen in a storage device in the form of a readable signal, for example, is proposed (see Japanese Unexamined Patent Application Publication No. 2001-211421, for example). The image management method allows a user to manually select a representative image from the successive images on the index screen. However, it is troublesome and time-consuming for the user to select a representative image for every set of successive images. In addition, the image management method is not intended for continuously captured photographs.
Also, an image output apparatus having a function for classifying image data into groups in accordance with meta data of the image data or attribute information on a person contained in the image data to extract a representative image for each group is proposed (see Japanese Unexamined Patent Application Publication No. 2008-146191, for example). The image output apparatus is configured to allow a user to select the conditions for extracting a representative image from each group. As possible conditions for selecting a representative image, there are mentioned whether the image is a group photograph or a portrait, the resolution level, the focus level, whether the image is a test shot (test-shot images are removed), the capture time interval, the designated capture location, and so forth. However, these extraction conditions are irrelevant to whether the subject is captured well or poorly in the images. Each group of image data classified in accordance with the meta data or the personal attribute information does not necessarily contain continuously captured photographs, which suggests that the image output apparatus is not necessarily intended for continuously captured images.
In addition, a digital camera that selects a representative shot from a plurality of continuous shots on the basis of an AF (Auto Focus) evaluation value obtained by extracting and integrating high-frequency components from image data for the plurality of shots is proposed (see Japanese Unexamined Patent Application Publication No. 2004-320487, for example). However, the digital camera does not select a representative shot in accordance with whether the subject is captured well or poorly in the images, although the digital camera is capable of automatically selecting a clear image from the plurality of shots to store the selected image in a storage device.